Depression and anxiety contribute significantly to death and disability worldwide, and they frequently occur together. Although antidepressants are widely used to treat these disorders, they typically exert only modest therapeutic efficacy after weeks of administration. In addition, antidepressants can initially worsen symptoms in some patients, they have serious side effects, and as many as one-third of patients who take them are resistant to their therapeutic effects. One reason that all antidepressants approved by the U.S. Food and Drug Administration to treat depression and anxiety perform sub-optimally is that they all exert actions on just three of the many signaling systems found in the brain. Therefore, drugs that target different brain systems are highly sought for in the development of new antidepressants.
Any feature or combination of features described herein are included within the scope of the present invention provided that the features included in any such combination are not mutually inconsistent as will be apparent from the context, this specification, and the knowledge of one of ordinary skill in the art. Additional advantages and aspects of the present invention are apparent in the following detailed description and claims.